Got my 12 yesterday, I have a navionics platinum card in my 998 C that is moving to the bow. Do I need a second card in the 12 or can they share a card by ethernet? Also what am I going to need to network them together? Thanks

They will share everything but the chip information. All you should need to newwork the two is an ethernet adapter for each unit and a cable. If you add anything else such as another sonar, 360, i-pilot link, then you'll need the 5 input ethernet box.

I'd consider buying a lakemaster card for it so then you'll have the best of both worlds. Some lakes are better on one card than the other. Your waypoints will still be shared if you turn sharing it on.